MurB, the product of the murB gene from Escherichia coli , is being investigated as an example of a potential new target for the design and development of novel antibacterial therapeutics. We are in the early stages of an MIR phasing effort on MurB and need to extend resolution and collect quality anomalous scattering data on potential derivatives, in particular a mercury derivative, and to collect high-quality, high-resolution data on crystals of MurB with cofactors and with substrate. We also need to collect MAD phasing data on crystals of a (SeMet)5-MurB mutant protein that has been prepared for our use.